The inauguration of the Gerostathopoulio University of Athens Observatory took place on Thursday 13 January 2000. The ceremony was attended by faculty members, astronomers from the National and Kapodistrian University of Athens and other institutes, students and members of the general public. Among the speakers were the Vice Rector of Financial Planning and Development, Professor G. Philokyprou, and the Dean of School Sciences, Prof. M. Dermitzakis. The Head of the Physics Department, at the time, Prof. P. Laskarides, gave a short introduction regarding the founding of the University of Athens Observatory and the status of relevant installations. Then, the Director of the Section of Astronomy, Astrophysics and Mechanics, at the time, Prof. P. Niarchos, gave a talk entitled "The role of small telescopes in the 21st century - The new 0.4-m telescope of the University of Athens". The donor of the telescope, Mr L. Gerostathopoulos, was subsequently presented with an honorary plaque by the Head of the Department of Physics. We should note that this donation was made possible thanks to Prof. P. Laskarides, whose contribution to the completion of this undertaking has been crucial. Prof. P. Niarchos, was primarily responsible for the installation of the telescope in 1999 and for its subsequent operations, while he was the instigator of the public events "Open nights - Astronomy for all", which continue successfully since the opening of the observatory (2000). At the end of the inauguration ceremony, three students who scored top marks in Astrophysics in 1999 received an award. The ceremony was followed by a small reception and a tour at the installations of the new telescope.